Rename jpeg files in a directory based on the date &time in EXIF metadata

pic_rename_by_exif.py

#!/usr/bin/env python3

import os
import os.path
import datetime
import argparse

from PIL import Image


EXIF_TAG_DATETIME = 306  # When taken or last edited
EXIF_TAG_DATETIMEORIGINAL = 36867  # When taken
#EXIF_TAG_DATETIMEDIGITIZED = 36868  # When stored as digital data
EXIF_TAG_SUBSECTIMEORIGINAL = 37521  # Franctions of secs for DateTimeOriginal

JPEG_SUFFIX = ".jpg"


def get_exif(filename):
    """Get dict with EXIF data"""
    image = Image.open(filename)
    image.verify()
    return image._getexif()


def get_datetime(exif):
    """Return datetime python object for date time data from EXIF"""

    # EXIF data time format example: "2019:12:22 16:52:40"

    if EXIF_TAG_DATETIMEORIGINAL in exif:
        raw_date_time = exif[EXIF_TAG_DATETIMEORIGINAL]
    elif EXIF_TAG_DATETIME in exif:
        raw_date_time = exif[EXIF_TAG_DATETIME]
    else:
        return None

    return datetime.datetime.strptime(raw_date_time, "%Y:%m:%d %H:%M:%S")


def rename(directory, test=False):
    """Rename file in the directory"""

    files = sorted(os.listdir(directory))

    mapping = {}

    for fn in files:
        if not fn.endswith((".jpg", ".JPG", ".jpeg", ".JPEG")):
            print("Skipping non JPEG file: {}".format(fn))
            continue

        filename = os.path.join(directory, fn)
        exif = get_exif(filename)
        dtobj = get_datetime(exif)

        # Pick new filename
        fn_prefix = os.path.join(
                        directory,
                        dtobj.strftime("%Y%m%d_%H%M%S")
            )

        newfn = fn_prefix + JPEG_SUFFIX

        if filename == newfn:
            # Nothing to do
            continue

        # If the file already exists, increment counter
        i = 1
        while os.path.exists(newfn):
            newfn = fn_prefix + "_" + str(i) + JPEG_SUFFIX
            i += 1

        mapping[filename] = newfn

    if not mapping:
        print("Nothing to do")
        return

    if test:
        print("Test mode used, printing what would be done...")
    else:
        print("Renaming...")

    for src, dest in mapping.items():
        print("{} -> {}".format(src, dest))
        if not test:
            os.rename(src, dest)

    if test:
        print("Test mode used, no rename was done!")


if __name__ == "__main__":

    parser = argparse.ArgumentParser(
        description="Rename jpeg files to YYYYMMDD-HHMMSS[-X].jpg " \
                    "format based on date &time data in EXIF metadata."
    )

    parser.add_argument(
        "directory",
        metavar="DIRECTORY",
        help="Directory where to rename the files."
    )
    parser.add_argument(
        "-t", "--test",
        action="store_true",
        help="Just print what would be done"
    )

    args = parser.parse_args()

    # Check args

    if not os.path.isdir(args.directory):
        parser.error(f"{args.directory} is not a directory!")

    rename(args.directory, test=args.test)